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The chemical bonding in a series of nickel mixed oxides, namely Li2NiO2, Na2NiO2, tetragonal and orthorhombic La2NiO4 for Ni(II), LiNiO2, NaNiO2, LaNiO3 for Ni(III), BaNiO3 for Ni(IV) and LaNiO2, 'LaSrNiO3' for Ni(I), is investigated from the results of electronic structure calculations, including both band structure and local properties, i.e. atomic charges, covalent bond orders and atomic valenc
A new quantum chemical definition is proposed of the full atomic valence, VA, taking into account both the covalent and ionic parts of the chemical bonds formed by atoms in molecules and crystals. The full atomic valencies, covalencies, and charges on atoms are calculated for nickel–oxygen crystalline compounds in the CNDO band theory approximation. A comparison of the chemical bonding in nickel a
The electronic structure of eleven crystalline nickel oxides was investigated by band theory - CNDO method. Both the band and local properties of the electronic structure were calculated and were used for the description of chemical bonding in Ni(II) (NiO, Li2NiO2, Na2NiO2, K2NiO2, BaNiO2, La2NiO4), Ni(III) (LiNiO2, NaNiO2, LaNiO3) and Ni(IV) (BaNiO3) compounds.
The interactions between dissolved organic matter (DOM) and mineral particles are critical for the stabilization of soil organic matter (SOM) in terrestrial ecosystems. The processing of DOM by ectomycorrhizal fungi contributes to the formation of mineral-stabilized SOM by two contrasting pathways: the extracellular transformation of DOM (ex vivo pathway) and the secretion of mineral-surface-react
Modelling from quantum chemical data of the chemical bonding in NiO and La2NiO4 crystals comparatively to CuO and La2CuO4, is proposed. The increase of the ionicity degree of the Ni(II)–O bonding in comparison with Cu(II)‐O bonding is observed. The covalency is low and equally distributed in the equatorial plane and apical direction in the NiO6 octahedra in La2NiO4. As a supplementary data, which
The band structure and local properties of La2O3 and LaF3 crystals are investigated within the framework of CNDO approximation.
The crystalline structure of lead oxides is rewieved. In the framework of LUC‐CNDO computational scheme the electronic structure of PbO, PbO2, Pb2O3, and Pb3O4 crystals is investigated. The results obtained are compared with experimental data.
A quantum‐chemical definition is proposed of the full atomic valence taking into account both, covalent and ionic components of chemical bonds formed by an atom in molecules or crystals. Atomic charges, covalent bond orders, and full atomic valencies of lead and oxygen atoms in the crystalline lead oxides are calculated in the framework of the LUC‐CNDO approach.
A new quantum-chemical definition is given of the full atomic valence taking into account both the covalent and ionic parts of the chemical bonds formed by an atom in molecules and crystals. Full valence is close to formal ("classical") valence of an atom in a wide row of compounds. The theoretical consideration and the CNDO calculations of molecules and crystals are made to justify the validity o
LUC‐CNDO computation scheme and its valence theory applications are discussed. Electronic structure calculations of well‐known semiconductors Cu2O are reviewed. The parameters of CNDO scheme for copper–oxygen compounds are calibrated using the results of Cu2O band theory calculations and experimental data.
The crystalline structure of copper‐oxygen compounds with copper atom in the oxidation states I, II, and III is reviewed. A calculation is made of the electronic structure of the row of crystals with copper‐oxygen bonding. It is shown that the covalence effects are essential for copper oxide compounds containing copper atoms in oxydation states CuII and CuIII LUC‐CNDO calculations of La2CuO4 and Y
AIMS: Failure of healing is a well-known problem after repair of the rotator cuff. This study aimed to investigate if early repair of trauma-related full-thickness rotator cuff tears (FTRCTs) could prevent this failure. PATIENTS AND METHODS: In this prospective trial, 62 consecutive patients (14 women (23%), 48 men (77%); median age 61 years (interquartile range (IQR) 54 to 65)) with trauma-relate
Different approaches to the theoretical study of the local centres in solids are discussed. Particular attention is paid to the embedded-cluster models. There are given the mathematical formulation, the computational scheme and applications for some local centres on/in graphite monolayers of the moderately large embedded cluster and the large-unit-cell-embedded-cluster (LUC-EC) models. It is shown
Objective Blood type A antigen on porcine aortic bioprostheses might initiate an immune reaction leading to an increased frequency of structural valve deterioration in patients with blood type B or O. The aim was to analyse the association between ABO blood type and porcine bioprosthetic aortic valve degeneration. Design Observational nationwide cohort study. Setting Swedish population-based study
